When casting director Debra Zane brought in the little-known actor Michael Shannon to tape an audition for “Revolutionary Road,” she pulled out all the stops.

Zane assembled a team to play the other roles, with friends and associates filling in for Leonardo DiCaprio, Kate Winslet and Kathy Bates.

“We were playing all the different parts, so he would have different faces to refer to. We had snacks and martini glasses to make it look like a little party,” explains Zane.

She got so into the scene that “when (Shannon) turned to tell me to shut up, I was so embarrassed, (which was) the absolute appropriate response.”

Director Sam Mendes, who has collaborated with Zane on five pictures, saw the tape and hired Shannon to play Bates’ mentally ill son. He went on to score the film’s only acting Oscar nomination this year.

A wiz at spotting breakout talent (Amy Adams, Wes Bentley, Justin Long), Zane has even been known to put together her own version of an actor’s reel to show a director that a performer can play against type.

When working on “Dreamgirls,” she spent eight months scouring talent from around the country. About 700 actors read for the part of Effie before director Bill Condon chose Jennifer Hudson for the part that would earn her an Oscar. But it was clear to Zane from the moment she saw the first of Hudson’s two audition tapes that the “American Idol” reject was a frontrunner.

“I can’t explain to you how people who work in casting know something like that,” she says, “because there are so many elements involved. It’s almost like a chemical reaction where you can say to yourself, ‘The director is going to love this person.'”

Zane has loved actors and movies ever since her childhood in Miami Beach. From an early age, she paid close attention to the “casting by” credit. “That credit struck me. I knew what it meant, and I knew I could do it because I was aware of actors in different roles.”

Nearly 20 years into her career, during which she has worked on such hits as “Traffic” and the “Ocean’s 11” trilogy, she’s still as passionate as when she began.

“I like making sure you’ve turned over every stone and thoroughly thought through all the angles,” says Zane. “And then it appears before your eyes.”